


Growing Up is Hard to Do

by BleedingInkBeatingHeart



Series: The Sarah Kate Rogers Universe [2]
Category: Captain America (Movies), Iron Man (Movies), Marvel Cinematic Universe, The Avengers (Marvel) - All Media Types
Genre: Alternate Universe, Can you tell I'm, Character Death, Civil War Team Iron Man, College, Consent is Sexy, Cunnilingus, Drugged Tony Stark, F/M, Friends With Benefits, Friends to Lovers, Growing Up, Growing Up Together, Howard Stark's Good Parenting, Hurt Tony Stark, Johnny Storm Cameo, Maria Stark's Good Parenting, Obadiah Stane sucks, Semi-Public Sex, Sex, Steve Rogers Daughter, Tony Stark Has A Heart, Tony Stark Needs a Hug, Underage Sex, Woman on Top
Language: English
Status: Completed
Published: 2021-01-08
Updated: 2021-01-08
Packaged: 2021-03-11 23:15:00
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,582
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28625550
Author URL: https://archiveofourown.org/users/BleedingInkBeatingHeart/pseuds/BleedingInkBeatingHeart
Summary: Katie and Tony grow up together. It was bound to happen eventually. Just don't tell Peggy... or Howard cause he'll just tell Peggy.
Relationships: Howard Stark/Maria Stark, Mary Parker/Richard Parker, Peggy Carter/Daniel Sousa, Tony Stark/Original Female Character(s)
Series: The Sarah Kate Rogers Universe [2]
Series URL: https://archiveofourown.org/series/2097291
Comments: 4
Kudos: 34





	Growing Up is Hard to Do

**Author's Note:**

> So this series began because I just kept thinking what if there were just one person constantly in Tony's corner. What if that person was someone Steve couldn't ignore? Someone who could make him sit and listen cause she was one who connected him to his past and to this present?
> 
> I don't own anything.

Tony age 10 almost 11, Katie age 10 like her birthday was recent.

Tony grinned as Katie ducked behind some curtains. He was walking with his dad through the house after the photographer for the magazine had left. He’d finished his first missile, and Howard wanted everyone to know that his kid was a genius. He put his hand on Tony’s shoulder.He kneeled down. “Your missile was great. I’m so proud of you for doing your part to help our country, but we need to talk about lab safety again.” He paused as Tony looked down. “I know you were in there without an adult. It’s the only way you could have finished your missile over night based on what I saw yesterday. What you were working on was very serious, very dangerous work, and it was incredibly dumb of you to work on it by yourself. You could have been hurt. You could have died, Tony…”

He paused to let that sink in. “There will never be another Tony Stark. You’re the only one there is, and I don’t want another kid because you’re the best kid I could have asked for.” He put his finger under Tony’s chin and lifted his face so their eyes could meet. “I’m so lucky to have you. I’m still proud of you, and I still love you. I just want you to wait until you’re 12 before you start working on the things by yourself, my little genius.” He ruffled his sons hair and kissed the top of his head, and with that, Tony was smiling once again.

Katie bounced out from behind the curtain. “BOO!”

Howard jumped before winking at Tony. “Little miss Rogers, what would your mother say about hiding behind curtains?”

She giggled. “She’d say that I should find better hiding spaces.”

Tony threw himself at her for a hug. “You weren’t here yesterday! I finished my missile!”

“I got my first period today!”

Tony froze as Howard started coughing. Aunt Peggy had literally just given them the Talk. He didn’t expect all this growing up and puberty stuff to start happening now. Still, he cleared his throat, remembering what she had taught him about how girls would prefer he respond. “Congratulations!” Cause it wasn’t about him and his sensitivities. It was about her and the women before her and their connection to each other and the world around them and the struggles they went through that made them stronger and more capable than he could ever imagine.

“Thank you!”

“Do you need anything? Cause I’ll get you anything, Katie.”

Howard snorted as Tony put his arm around his best friend and started leading her to his little lab.

Howard walked over to the hall phone and dialed Peggy’s SHIELD number.

“Hello.”

“Hey, Peg.”

“Is everything okay, Howard?”

“Yeah, just wanted to let you know your little girl is a woman now.”

Peggy sighed. “I told her to stop telling people.”

“You told her it was something to be proud of. Why shouldn’t she share it if she’s proud of it?”

“Don’t tell me you’re laughing right now.”

“I’m not… If our kids don’t get together, I’ll eat my left shoe.”

“Howard, stop betting on them.”

“Come on.”

“Katie is too sensible to date your son. Tony is too much of a dreamer.”

“Well, that’s good. I raised him to be a dreamer and reach for whatever he wanted without trampling over people. I’ve done a pretty good job thus far… I’m thinking of taking him on my annual voyage.”

“I don’t think you should. It’s cold. The boat doesn’t have a lab or any type of computer. He’d get bored without something to keep his interest.”

“I’m gonna build him a boat with things he loves on it. That way we can go sailing and he can do what he loves while doing something out in the world.”

“Right… I’m hanging up now…”

“Hey, dinner on Friday! We need you to bring something English. We’re having a culture dinner. Maria’s making pasta. I’ve ordered in some cannoli’s to represent Steve and I’m making brisket. Ana and Edwin are bringing cabbage rolls, which Maria has been excited to try. Tell Dannyboy to bring something Idahoan. I don’t know. Like potatoes.”

“I’ll let him now. I’ll bring a plum pudding or something. I’ll have to think about it. I’ll see you later today to get Katie?”

“Why bother? You and Dan have a couple free days. Maria and I got her till Friday… Then you get Tony for the weekend?”

“That sounds wonderful.”

“When they’re dating, these sleepovers have to stop.”

“Howard!”

“I don’t want to be a grandfather when Tony is sixteen, Peggy!”

“Goodbye, Howard!”

* * *

Katie was fourteen and Tony was fifteen when they kissed each other for the first time. Their first goodbye. All the tutoring sessions and lab time and personal teaching from Howard Stark meant that they both were ahead of their age. Not to mention Katie had her bio-father’s memory and tactical mind. Meanwhile, Tony was a Stark, and MIT was anxiously waiting for him to arrive. She was Peggy Carter’s daughter, so of course every school in the world would have let her in, including MIT, but she chose Princeton. Their biochemical engineering and genetics programs caught her eye, and, while not many knew her father was actually Steve Rogers, no one could deny her impossible resemblance to him. Except her smile. Her smile was all her mother.

The kiss was clumsy and awkward but full of a love they’d never really spoken of before. They’d grown up learning that true love was a fairy tale. Real relationships needed more than just a sudden kiss. But they’d needed that kiss to push them on to separate flights where they would both think to themselves. _I should have went with her/him_.

Meanwhile, Howard was gleefully taking pictures of that sloppy kiss with a disposable camera while Dan stopped Peggy from slapping the millionaire and Maria cried over her baby’s first steps to adulthood.

* * *

Katie’s roommate was really into KISS, her boyfriend, and pretending she didn’t exist. Which was fine because Katelyn spent so much time in the lab performing various experiments and analyzing samples of whatever biological material she could find that it left no time for bonding with her roommate.

Tony had Rhodey.

Loyal Rhodey.

Caring Rhodey.

Wouldn’t take shit Rhodey.

Rhodey would drive him five hours to see her. He would take care of him when he was drunk or stoned or just having a bad day.

He’d hold his hand when Howard got onto him about wasting his potential, drinking and smoking. For God’s sake, he was 15. Couldn’t he just wait until his father was dead before he started trying to destroy his beautiful brain? The last part was said in jest, but it got the point across.

* * *

Tony and Katie had sex for the first time in a forest in upstate New York, trying to get away from Sharon, Katie’s cousin, and Peggy’s new SHIELD friend, Nick. They’d found their old treehouse and smuggled up a few blankets and a bottle of vodka. She’d kept her bra on the whole time, but he didn’t mind at all as long as she kept making those noises. He’d remembered The Talk with Aunt Peggy seven years earlier. Ladies first. And buried his face in her. He’d nipped and sucked and licked, finding he could do this forever with her just so she could have release over and over again.

She came once in his mouth, panting slightly drawing him into a kiss before whispering, “Next time I go down on you first.” He grinned wildly as she flipped them over. She tugged his pants and underwear down in one motion, springing his erection free. For a second she stared at it. For a brief second, she wanted to comment on how she’d only ever seen penises in porn or in dissections, but instead she kissed it, watching it bob a little as she tasted the precum on her lips. She lined him up with her entrance and slowly sunk down giving herself and him time to adjust. He bit the inside of his cheek trying not to explode inside her so soon.

Then after she was fully seated, she moved. And oh god! That was. Perfect. She was perfect. He flipped them, loving the gasp/giggle she made as he did. Every thrust into her was like coming home, but he felt his end coming fast. He brought his hand down to her clit, trying to work another orgasm from her body. He was rewarded when she clenched around him, screaming his name. A second later, he pulled out screaming hers. White fluid hit her bare stomach as they both continued staring into each other’s eyes.

Fucking Sharon yelled from the bottom of the tree. “To-to, Kay Kay! You up there?”

Tony started helping her clean off with one of the blankets as she yelled, “Sharon, I swear to God I will fucking end you if you come up here right now! You got me?”

“I’ll tell Aunt Peggy,” she said, kicking the tree.

“I’ll hide your tiny body in a cadaver,” she deadpanned. Tony tried to hand her back her panties, but she just shoved them in his pocket and pulled on her leggings.

Sharon huffed. “Fine.” She stomped away loudly as Tony handed her her dress. She pulled it on and folded the blanket so no one could see the mess they were bringing in.

They stared at each other. The shift in their friendship visible only to them.

“That was-“

“You were-“

They both chuckled. Tony’s face softened. “I would never hurt you. You’re my everything.”

She blushed. “And you’re mine. I... I love you.”

He kissed her. “I love you.”

They started down the treehouse when something occurred to her. “We need to buy some condoms, and I need to visit my doctor. No kids!”

“Not now at least,” he said as they made it to the bottom.

She whipped around to look at him. “You’re kidding right? Have you seen Sharon? You really want one of those running around the mansion.”

“Obviously not,” he held her hand. “We would never have a kid like Sharon, and neither of us like this mansion. I’m thinking New York or LA. Maybe. What do you think of Malibu?”

They started walking back to their families, speaking of architectural designs and their future joint lab and maybe just maybe when they were ready a little blue eyed brunette baby that would be strong and smart and trouble.

When they got back inside, Howard was grinning like a mad man. Nick Fury looked disturbed, and Peggy looked like she’d swallowed a lemon. Dan was pinching the bridge of his nose as Maria, clearly drunk after too much spiked punch, hugged them both, saying, “I’m so proud of you, my sweet boy. It sounded like it was a lot of fun for the two of you… So proud… And Katie, sweetie, if pregnancy happens, it happens, and it’s a beautiful thing… Oh! Don’t you think they’ll make the best babies?! Mary, what do you think?”

Mary, Katie’s sister, was sitting quietly next to her husband Richard. “I think they’re a bit too young to be having sex.”

Tony’s face was bright red. He really didn’t think that they’d been that loud. Katie was smirking. “Well, lucky for you, sis. I control my own body… Since the cat is out of the bag… Yes, we had sex. It was fun, and we’re making plans to follow through with responsible actions to avoid certain issues…”

“Issues like what?” Howard exclaimed joyously. “This is exciting. My son’s found love! If you get pregnant, it’s fine. You two can just move in with us, and we’ll help out. Oh! Peggy, we’re gonna be grandparents!”

At that, Peggy slapped him, and everyone was too focused on the ensuing argument to notice Tony and Katie slip from the room holding hands.

* * *

The next day Tony’s parents died in a car crash. They both knew there was some covering up going on because Nick was there. He told the household, and, surprisingly, he stayed with them. Peggy was grateful, but Tony knew the truth. He didn’t want anyone questioning him.

Drunken accident. That’s what they said, but Howard hadn’t had a real drink in years… This was insane. Katie stormed up to Nick as he continued to stare at her.

“Rogers.”

“Fury.”

“Why the fuck are you looking at me like that?”

“Car accidents are suspicious when they involve high profile people, don’t you think?”

“I do think,” he assured her. “Which is why I had my man, Peirce, look into it. Pure accident.”

She snorted. “Right. This sounds weird.”

Fury stared at her for a moment, his one good eye narrowed at her. “Don’t go telling people your suspicions. Howard Stark was a good man. He deserves to Rest In Peace without his kid or his kid’s girlfriend screwing that up…”

“Ha! Uncle Howard lived in a state of half chaos ninety percent of the time.” He frowned at her so she continued, “Tell me more about this accident. What did your man find?”

“Black ice. He slipped on black ice on his way back from the gala.”

“Hmm.”

Nick froze, looking her up and down. “So the rumors are true?”

She quirked an eyebrow. He gave a soft chuckle. “Stark probably loved his kid being with you more than anything in the world.”

“Apparently, he was betting on it. Now, what are you talking about?” she hissed.

“I see it now. You look almost like the perfect mix of Carter and Rogers.”

She froze before the words just flew out of her mouth. “You can’t tell SHIELD cause Mama will kill you, and Tony will make sure you and your buddies never existed.”

He grinned. “I’ll keep your secret, Rogers, but not because of those threats. I take my Uncle duties very seriously.”

She frowned. “Okay... What the actual fuck, man?”

“Your mom has been talking about who would take care of y’all if something happened to her.” He shrugged. “You got me.”

“Black James Bond?”

“Hey, don’t talk to your favorite Uncle like that? I’m way better than James Bond”

She walked off shaking her head. She and Tony split a huge bottle of bourbon and fell asleep in his parents' bed. The next day Obadiah basically dragged him back to school.

* * *

Tony ended up on the cover of some magazine six months later in some random girl’s bed. Rhodey told her he was drunk. Then he graduated and he ditched her at the party so he could go fuck some brunette. Then he basically disappeared for another six months. He could talk to Rhodey but not to her. Then his 19th birthday came around. The second one since his parents’s death. Rhodey’d come to pick her up, which was surprising because normally Tony was with him. He was already drunk when she found him, whispering into the cleavage of another blonde. For a moment, she forgot to be angry because she knew her best friend and this wasn’t him. She grabbed him and dragged him away, ignoring the camera flashing and the bimbo calling out behind her. She pulled him into a closet under the stairs. “What’s going on?”

“What do you mean what’s going on? It’s a party. A lot’s going on.”

“Don’t be a dick.”

“I’m not-“

“You’re not being you!”

“Not being me?” He looked at her with eyes so cold she almost flinched. “And what am I supposed to be doing? Bending to your will? Getting married at 19?”

She shook her head, confused. “Whoa, what? What the fuck, Tony?”

“You’re just using me!” He shouted at her. “Trying to trap me!”

“Oh, yeah!” She sneered, throwing her hands up in the air. “We became friends at the age of one so I could trap you into marrying me 15 years later! You’re not that stupid!”

“No, you’re the one being stupid. Did you think I wouldn’t figure it out?”

“Okay, seriously, what the fuck is going on right now? Have you been doing cocaine or some shit?”

“Stop it!”

“Stop what?” She asked incredulously.

“Stop acting like you give a damn about me! I’ve had enough of your act.”

“What act, asshole?!”

He grabbed her shoulders and looked into her eyes. “I loved you and you broke my heart. Why would I ever trust you again?”

“Tony, I’m so confused,” she felt tears coming to her eyes. “Just tell me what you think I did.”

He licked his dry lips. “Obie told me about how Aunt Peggy talked about us getting married all the time when we were babies. He said he didn’t realize she’d been pushing you so hard to seduce me.”

She swallowed before shaking her head. “First of all, If anyone was pushing us together, it was your dad. He took pictures of our first kiss for fuck’s sake. Second of all, how could you believe him over people who’ve been there for you since you were a baby? We love you, Tony.”

“Obie’s my godfather and my business partner.”

“Mama’s your godmother and I’m... Tony, you’re my everything.”

He let her go and looked away. “How do I know you’re not lying to me?”

Her face crumpled for a second before her anger filled her. “Fine. If you just want to forget everything we’ve been through, then fuck you too!”

She broke the lock on the door when she pushed it open. She was trying to leave as stealthy as possible, but Johnny Storm cut her off at the doorway. “Whoa there, lil Rogers!”

She pinched the bridge of her nose. “Look, Johnny, I can’t fucking stand you at school. Why would a change of scenery change that fact?”

“You just looked a little blue, Blondie.”

He reached for her elbow. “Why don’t you and I go somewhere more private to talk?”

“Why the fuck-“

A fist slammed into Johnny’s jaw and he fell to the ground. Tony put an arm around her. “You mess with my best friend again, Storm, and I’ll make sure you’re on the no fly list for the next ten years.” Tony gestured to the new security guy, Happy. “Get him out of here.”

Katelyn shrugged his arm off her shoulder and he flinched. “Did you get diagnosed with something I should know about?”

He grabbed her hand and pulled her outside. “I’m sorry. I shouldn’t have... Obie... He, uh, got in my head. I got a bit-“

“Confused?”

He nodded. “You’re my best friend, and you’ve always been there for me through everything. And we’ve had sex... made love.”

“Gross.”

“Right, and I love you, but maybe-“

“Take it slow. Come together later.”

“Yeah. In life and in bed.”

She laughed. “Maybe space will be good for us for a little bit.”

“Maybe.” He paused. “I’m gonna tell Obie to leave the topic of you alone.”

“Can’t believe you listened to him anyway.”

“I’ve been a bit vulnerable lately. Obie gave me these pills to help. Anti depressants, I think.” He held up the pill bottle.

She grabbed it and looked at the label. Yeah, it was an anxiety medication, but when she lifted the bottle to the light, she noticed the pills weren’t the right shape. She knew from her pharmacology labs and clinicals what the pills were supposed to look like. Little white circles. Not orange octagons. She bit her lip, opened the bottle, and pulled out a pill. She squeezed it in her fingers, and it smoothed into white powder. She rubbed her fingers together before she licked it. Bitter and then her tongue went numb. She looked at her best friend in horror. “I was totally joking earlier, I promise! This is cocaine, Tony!”

His eyes widened. “No. No way. I’ve been on these pills for anxiety for a year. Not cocaine.”

“Tony,” she held up her finger. “My tongue is numb, and it’s not that hard to paint a pressed pill.”

He forehead. “But Obie-“

“Obie is the one who gave you these pills. That doesn’t mean he knew what they were.”

There was a pause before he scuffed his shoe on the pavement. “I’m sorry about sleeping with other women.”

“It’s okay... I, uh, I slept with my lab partner.”

“What?”

“Oh so it’s okay for-“

“No, that’s not what I mean. I meant you hate your lab partner. Why would sleep with him?”

She rolled her eyes. “I got a new one... granted I don’t like him much either, but this is my third doctorate and I don’t really get the luxury of having real colleagues now.”

They talked more than they’d talked since his parents had died. Tony agreed to go to rehab for the pills so someone would be there to monitor him. Katie agreed to call more. They both agreed never to fully trust Obadiah Stane. They also agreed that maybe they should take a break till they were ready for something more serious. She went home that night feeling relieved. He went home feeling pissed at himself for not realizing something was wrong with him. Then he grabbed a glass of scotch and started designing a new A.I., someone who could take care of him when Katie was gone.

**Author's Note:**

> Y'all, can you just imagine Steve's shock when he finds out?


End file.
